This invention relates to substance detection based upon substance dielectric characteristics, and more specifically to apparatus and a method utilizing near-field microwave technology for detecting and identifying the presence (dielectric xe2x80x9csignaturesxe2x80x9d) of selected kinds of substances which are hidden behind an electrically conductive metal expanse.
While there are many fields of application for this invention, a preferred and best mode embodiment of, and manner of practicing, the invention are described and illustrated herein in the context of detecting contraband and/or dangerous substances, such as certain drugs and explosives, which may be carried clandestinely concealed in otherwise innocuous, sealed metal containers, such as in cans of olive oil.
Near-field microwave technology has established itself as a powerful and versatile tool for detecting, via observing dielectric characteristics of, various substances that prove to be illusive, even invisible, to other detection modes. This technology and its detection capability are timely, and are of great interest today especially in the heightened sense of concern that people feel and express for personal security in places such as airports and aircraft.
A number of now-issued U.S. patents describe and attest to the power and versatility of microwave detection practices, and these patents include:
U.S. Pat. No. 4,234,844, Electromagnetic Noncontacting Measuring Apparatus
U.S. Pat. No. 4,318,108, Bidirectionally Focussing Antenna
U.S. Pat. No. 4,532,939, Noncontacting, Hyperthermia method and Apparatus of Destroying Living Tissue in Vivo
U.S. Pat. No. 4,878,059, Farfield/Nearfield Transmission/Reception Antenna
U.S. Pat. No. 4,912,982, Non-Perturbing Cavity Method and Apparatus for Measuring Certain Parameters of Fluid Within a Conduit
U.S. Pat. No. 4,947,848, Dielectric-Constant Change Monitoring
U.S. Pat. No. 4,949,094, Nearfield/Farfield Antenna with Parasitic Array
U.S. Pat. No. 4,975,968, Timed Dielectrometry Surveillance Method and Apparatus
U.S. Pat. No. 5,083,089, Fluid Moisture Ratio Monitoring Method and Apparatus
U.S. Pat. No. 6,057,761, Security System and Method
The contents of each of these just-mentioned patents are hereby incorporated herein by reference.
The present invention, while based in part upon certain structures and methodologies expressed in these patents, makes a significant departure in the form of my recent discovery that, under special structural and methodologic circumstances, it is possible to employ nearfield microwave technology effectively to xe2x80x9csee throughxe2x80x9d an otherwise, and normally thought of, occluding barrier expanse of conductive metal, thus to detect various metal-hidden substances of societal concern, such as illegal drugs, and explosives. Prior detection approaches utilizing the specific technology described in the patents listed above have, by contrast, involve substance detection through shrouding or intervening media which is not formed of metal. By including the new capabilities offered by the present invention, the xe2x80x9cescape hatchxe2x80x9d of metallic hiding or shrouding employed by those engaged in such practices is easily and significantly checked.
The manners of implementing and practicing this invention, and their respective advantages and contributions to the art, will become quite fully apparent from the following detailed descriptions of the preferred and best mode embodiment, and manner of practicing, the invention, especially as read in light of the accompanying illustrative drawings.